Mild: Conjunctival pallor and/or of tongue
Moderate: Conjunctival pallor and/or of tongue + palmer pallor
Severe: Conjunctival pallor and/or of tongue + palmer pallor + pallor of palmar creases.
Reference:
Regina D et al. Correlation of pallor with hemoglobin levels and clinical profile of anemia in primary and middle school children of rural Telangana. Int J Contemp Pediatr. 2016 Aug;3(3):872-877
Pallor and its grading: http://www.ihatepsm.com/blog/pallor-and-its-grading